Re: [PATCH for 6.2?] Revert "vga: don't abort when adding a duplicate isa-vga device"

["Alex Bennée" <alex.bennee@linaro.org>]

Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> writes:

> On 02/12/2021 17:14, Cornelia Huck wrote:
>
>> On Thu, Dec 02 2021, Alex Bennée <alex.bennee@linaro.org> wrote:
>> 
>>> This reverts commit 7852a77f598635a67a222b6c1463c8b46098aed2.
>>>
>>> The check is bogus as it ends up finding itself and falling over.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> Resolves: https://gitlab.com/qemu-project/qemu.git/-/issues/733
>>> ---
>>>   hw/display/vga-isa.c | 10 ----------
>>>   1 file changed, 10 deletions(-)
>>>
>>> diff --git a/hw/display/vga-isa.c b/hw/display/vga-isa.c
>>> index 8cea84f2be..90851e730b 100644
>>> --- a/hw/display/vga-isa.c
>>> +++ b/hw/display/vga-isa.c
>>> @@ -33,7 +33,6 @@
>>>   #include "hw/loader.h"
>>>   #include "hw/qdev-properties.h"
>>>   #include "qom/object.h"
>>> -#include "qapi/error.h"
>>>     #define TYPE_ISA_VGA "isa-vga"
>>>   OBJECT_DECLARE_SIMPLE_TYPE(ISAVGAState, ISA_VGA)
>>> @@ -62,15 +61,6 @@ static void vga_isa_realizefn(DeviceState *dev, Error **errp)
>>>       MemoryRegion *vga_io_memory;
>>>       const MemoryRegionPortio *vga_ports, *vbe_ports;
>>>   -    /*
>>> -     * make sure this device is not being added twice, if so
>>> -     * exit without crashing qemu
>>> -     */
>>> -    if (object_resolve_path_type("", TYPE_ISA_VGA, NULL)) {
>> Don't you simply need to invert the check? You should get NULL back
>> if
>> there is another device already...
>
> Yes that's correct - the existing check is simply missing a ! at the
> front. For an existing example take a look at the the fw_cfg device:
>
> https://gitlab.com/qemu-project/qemu/-/blob/master/hw/nvram/fw_cfg.c#L1228
> https://gitlab.com/qemu-project/qemu/-/blob/master/hw/nvram/fw_cfg.c#L1125
>
> Unfortunately it seems that I also missed this when I added my R-B tag
> :(

Although that doesn't seem to fix the original problem:

  ➜  ./qemu-system-x86_64 -name ELKS -machine isapc -cpu 486,tsc -m 1M -vga std -rtc base=utc -netdev user,id=mynet,hostfwd=tcp:127.0.0.1:8080-10.0.2.15:80,hostfwd=tcp:127.0.0
  .1:2323-10.0.2.15:23 -device ne2k_isa,irq=12,netdev=mynet -drive if=ide,format=raw,file=$HOME/images/qemu.advent/day23/hd32mbr-fat.bin -drive if=ide,format=qcow2,file=$HOME/images/qemu.advent/day23/scratch.qcow2 -serial mon:stdio
  QEMU 6.1.93 monitor - type 'help' for more information
  (qemu) quit
  🕙10:23:50 alex@zen:qemu.git/builds/all  on  plugins/upgrade-insn-tracking-plugin [$!?] took 5s 
  ➜  ./qemu-system-mips64el -M pica61 -device isa-vga
  RAMBlock "vga.vram" already registered, abort!
  fish: “./qemu-system-mips64el -M pica6…” terminated by signal SIGABRT (Abort)
  🕙10:23:54 alex@zen:qemu.git/builds/all  on  plugins/upgrade-insn-tracking-plugin [$!?] [⚡ IOT] 

>
>
> ATB,
>
> Mark.


-- 
Alex Bennée